The present invention relates to a liquid dispensing system, particularly to a soap dispensing cabinet wherein incremental amounts of soap can be dispensed in response to actuation by a user.
A number of liquid soap dispensers are known. U.S. Pat. No. 4,349,133, U.S. Pat. No. 4,546,904, U.S. Pat. No. 4,667,854 and U.S. Pat. No. 4,463,876 are examples of such dispensers.
U.S. Pat. No. 4,349,133 discloses a liquid dispenser and refill package. The dispenser has a housing, flexible plastic pouch, pumping mechanism and a check valve mechanism. The housing provides a front half and a rear half joined together by a hinge. A pouch located within the housing includes a reservoir and a tubular pumping section in fluid communication with the reservoir.
A "duck bill" check valve for preventing liquid leakage from the pumping section is located at the free end of the pumping section of the pouch. In FIG. 6 of U.S. Pat. No. 4,349,133, the "duck bill" check valve is illustrated. The "duck bill" valve is a plastic cylindrical closure having a diametric slit thereacross which is normally closed but openable when the liquid is pressurized by the pump. The pumping mechanism is contained within the housing and comprises a first block and a second block which sandwich the pumping section and squeeze the pumping section when forced together. The second block is mounted on a lever hinged to the housing. The lever actuates the pumping mechanism when grasped and pulled forward.
U.S. Pat. No. 4,546,904 is similar to U.S. Pat. No. 4,349,133. A check valve is provided in this device. The check valve can comprise one of two embodiments: a first embodiment is a ball and spring valve (see FIG. 5); and a second embodiment is a slit diaphragm valve (see FIG. 4).
U.S. Pat. No. 4,667,854 discloses a liquid dispenser having a roller which travels along the length of the pumping section. A check valve is provided which comprises a nozzle which has a small opening.
U.S. Pat. No. 4,463,876 discloses a pouch liquid dispenser system having a reservoir section, a pumping section, and a discharge nozzle.
U.S. Pat. No. 4,932,562, which names one of the two inventors of the instant invention as an inventor, discloses a liquid dispensing system. The system includes a compressible housing holding a flexible pouch therein for storing liquid such as soap. A valve mechanism for checking the flow of the liquid from the pouch is provided that includes a mechanism for laterally tensioning the pouch proximate its discharge nozzle.
Although the prior dispensers provide apparatus that can be used to dispense a liquid, such as soap, they suffer a number of disadvantages.
A number of the systems are unnecessarily complex in structure and operation. As a result, these systems are difficult and expensive to manufacture and maintain.
Additional limitations with respect to some dispensers include a slow response (rate of product flow) of the pump section refilling with fluids; a failure of the system to sufficiently "suck-back" fluid at the conclusion of the discharge stroke; and wear and tear on the tube section due to the need to achieve an absolute shut off of the supply side of the fluid system.